A heterogeneous network (Heterogeneous Network, HetNet) can effectively improve the current network system throughput, and is one of the hot topics of 3GPP standards currently discussed.
The existing HetNet may include one macro NodeB and multiple micro NodeBs. A user equipment (User Equipment, UE) selects a NodeB for access based on reference signal received power (Reference Signal Receiving Power, RSRP) of the NodeB; and after selecting the NodeB for access, the UE uses the NodeB as both the uplink serving node and downlink serving node of the UE. The process in which the UE selects a NodeB for access may be specified as follows: The UE measures the RSRP of reference signals sent by each NodeB (including a macro NodeB and a micro NodeB), then selects a NodeB of the best RSRP signal quality for access, and uses the NodeB as the uplink serving node and downlink serving node of the UE.
In the HetNet, the transmit power of the micro NodeB is far lower than the transmit power of the macro NodeB. For example, typically the transmit power of the macro NodeB is 46 dBm, while that of the micro NodeB is 24 dBm or 30 dBm, and the difference between them is 40-160 times. Because the RSRP of the macro NodeB detected by the UE is usually greater than that of the micro NodeB, in the process of selecting a NodeB for access, usually the existing UE tends to access the macro NodeB. Consequently, the coverage area of the macro NodeB is far greater than that of the micro NodeB, resulting in load imbalance between the macro NodeB and the micro NodeB and a low system capacity.